Skip to content

Zeina Beidas

Department of Psychology, University of Toronto Mississauga, Mississauga, Canada.

3 papers in the library · 12 citations · publishing 2024-2025

Papers

Global Trends in Psychedelic Microdosing: Demographics, Substance Testing Behavior, and Patterns of Use

Journal of Psychoactive Drugs November 6, 2024 Rotem Petranker, Valentyn Sobolenko, Zeina Beidas et al. 9 citations

People who exclusively microdose psychedelics differ from those who also take larger doses. Exclusive microdosers are older (average 46.4 vs. 42.0 years), more often female (68.4% vs. 44.7%), non-Caucasian (25.4% vs. 14.7%), and urban residents (43.9% vs. 38.5%). They report using fewer non-psychedelic substances over their lifetime (3.8 vs. 4.7 substances). Most microdose multiple times a month (52.5%), commonly using psilocybin (74.5%), LSD (34.4%), or ketamine (15.8%), and 64.6% do not test their substances. The main reason for microdosing is improving general wellbeing (73.0%).

Preferences, Perceptions, and Environmental Considerations of Natural and Synthetic Psychedelic Substances: Findings from the Global Psychedelic Survey

Journal of Psychoactive Drugs December 24, 2024 Omer A Syed, Rotem Petranker, Emily C Fewster et al. 3 citations

A strong preference for natural over synthetic sources exists among users of psilocybin (75%), DMT (56%), and mescaline (56%), based on an anonymous online survey of 6,379 consumers from 85 countries. About half of respondents (50.8%) believe the source affects a psychedelic's psychological and physiological effects, while 34.4% are neutral. Despite preferring natural sources, 67.7% would switch to synthetic alternatives if it reduced environmental harm from overharvesting. The survey's respondents came mainly from anglophone regions.

Microdosing Psilocybin for Major Depressive Disorder: Study Protocol for a Phase II Double-Blind Placebo-Controlled Randomized Partial Crossover Trial

November 16, 2025 Zeina Beidas, Anya Ragnhildstveit, Adam Blackman et al. preprint

A phase II trial will test whether microdosing psilocybin (2 mg weekly) outperforms placebo for major depressive disorder. Forty adults will receive either psilocybin or placebo for four weeks, then all will receive psilocybin for another four weeks. Depression symptoms and other measures will be assessed at baseline, after four weeks, and after eight weeks, with follow-ups for two years. The study aims to clarify whether microdosing has genuine antidepressant effects or whether benefits are due to expectancy, and to inform future dose regimens and the therapeutic role of sub-threshold versus threshold doses.